492 research outputs found

### Ionization potentials and polarizabilities of superheavy elements from Db to Cn ($Z$=105 to 112)

Relativistic Hartree-Fock and random phase approximation methods for open
shells are used to calculate ionization potentials and static scalar
polarizabilities of eight superheavy elements with open $6d$-shell, which
include Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn ($Z$=105 to 112). Inter-electron
correlations are taken into account with the use of the semi-empirical
polarization potential. Its parameters are chosen to fit the known ionization
potentials of lighter atoms. Calculations for lighter atoms are also used to
illustrate the accuracy of the approach.Comment: 5 papers, 4 tables, no figure

### Combination of the single-double coupled cluster and the configuration interaction methods; application to barium, lutetium and their ions

A version of the method of accurate calculations for few valence-electron
atoms which combines linearized single-double coupled cluster method with the
configuration interaction technique is presented. The use of the method is
illustrated by calculations of the energy levels for Ba, Ba$^+$, Lu, Lu$^+$ and
Lu$^{2+}$. Good agreement with experiment is demonstrated and comparison with
previous version of the method (Safronova {\em et al}, PRA {\bf 80}, 012516
(2009)) is made.Comment: 7 pages, 5 tables, no figure

### Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

Hyperfine-induced electric dipole contributions may significantly increase
probabilities of otherwise very weak electric octupole and magnetic quadrupole
atomic clock transitions (e.g. transitions between $s$ and $f$ electron
orbitals). These transitions can be used for exceptionally accurate atomic
clocks, quantum information processing and search for dark matter. They are
very sensitive to new physics beyond the Standard Model, such as temporal
variation of the fine structure constant, the Lorentz invariance and Einstein
equivalence principle violation. We formulate conditions under which the
hyperfine-induced electric dipole contribution dominates. Due to the hyperfine
quenching the electric octupole clock transition in $^{173}$Yb$^+$ is two
orders of magnitude stronger than that in currently used $^{171}$Yb$^+$. Some
enhancement is found in $^{143}$Nd$^{13+}$, $^{149}$Pm$^{14+}$,
$^{147}$Sm$^{14+}$, and $^{147}$Sm$^{15+}$ ions.Comment: 5 papers, 3 tables, no figure

### Current trends in searches for new physics using measurements of parity violation and electric dipole moments in atoms and molecules

We review current status of the study of parity and time invariance phenomena
in atoms, nuclei and molecules. We focus on three most promising areas of
research: (i) parity non-conservation in a chain of isotopes, (ii) search for
nuclear anapole moments, and (iii) search for permanent electric dipole moments
(EDM) of atoms and molecules which are caused by either, electron EDM or
nuclear $T,P$-odd moments such as nuclear EDM and nuclear Schiff moment.Comment: 6 pages; the article is based on invited talk at the Workshop on
Fundamental Physics using atoms (FPUA2010), 7-9 August, 2010, Osaka, Japa

### Atomic optical clocks and search for variation of the fine structure constant

Theories unifying gravity and other interactions suggest the possibility of
spatial and temporal variation of physical ``constants''. Accuracy achieved for
the atomic optical frequency standards (optical clocks) approaches the level
when possible time evolution of the fine structure constant $\alpha$ can be
studied by comparisons of rates between clocks based on different atomic
transitions in different atoms. The sensitivity to variation of $\alpha$ is due
to relativistic corrections which are different in different atoms ($\sim
Z^2\alpha^2$). We have calculated the values of the relativistic energy shifts
in In II, Tl II, Ba II and Ra II which all can be used as atomic optical
clocks. The results are to be used to translate any change in the clock's rate
into variation of $\alpha$.Comment: 5 pages; LaTeX; Submitted to Phys. Rev.

### Calculation of parity non-conservation in xenon and mercury

We use configuration interaction technique to calculate parity
non-conservation (PNC) in metastable Xe and Hg [proposal of the experiment in
L. Bougas et al, Phys. Rev. Lett. 108, 210801 (2012)]. Both, nuclear
spin-independent and nuclear spin-dependent (dominated by the nuclear anapole
moment) parts of the amplitude are considered. The amplitudes are strongly
enhanced by proximity of the states of opposite parity.Comment: 8 pages, 5 tables, no figure

### Parity nonconservation in hyperfine transitions

We use relativistic Hartree-Fock and correlation potential methods to
calculate nuclear spin-dependent parity non-conserving amplitudes (dominated by
the nuclear anapole moment) between hyperfine structure components of the
ground state of odd isotopes of K, Rb, Cs, Ba+, Yb+, Tl, Fr, and Ra+. The
results are to be used for interpretation of current and future measurements.Comment: 5 pages, 3 tables, no figure

### Theoretical study of the experimentally important states of dysprosium

Configuration interaction method is used to calculate transition amplitudes
and other properties of the low states of dysprosium which are used in cooling
and in study of the time variation of the fine structure constant and violation
of fundamental symmetries. The branching ratio for the cooling state to decay
to states other than ground state is found to be smaller than $10^{-4}$. The
matrix element of the weak interaction between degenerate states at
$E=19797.96$ cm$^{-1}$ is about 2 Hz which is consistent with the experimental
limit $|H_W| = |2.3 \pm 2.9({\rm statistical}) \pm 0.7({\rm systematic})|$ Hz
[A. T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Phys. Rev. A {\bf 56},
3453 (1997)] and points to feasibility of its experimental measurement.
Applications include search for physics beyond the standard model using the PNC
isotopic chain approach.Comment: 5 pages, 5 tables, no figure

### Calculation of the (T,P)-odd Electric Dipole Moment of Thallium

Parity and time invariance violating electric dipole moment of $^{205}$Tl is
calculated using the relativistic Hartree-Fock and configuration interaction
methods and the many-body perturbation theory. Contributions from the
interaction of the electron electric dipole moments with internal electric
field and scalar-pseudoscalar electron-nucleon (T,P)-odd interaction are
considered. The results are $d(^{205}{\rm Tl})=-582(20) d_e$ or $d(^{205}{\rm
Tl})=-7.0(2)\times 10^{-18}C^{SP} e {\rm cm}$. Interpretation of the
measurements are discussed. The results of similar calculations for $^{133}$Cs
are $d(^{133}{\rm Cs})=124(4) d_e$ or $d(^{133}{\rm Cs})=0.76(2)\times
10^{-18}C^{SP} e {\rm cm}$.Comment: 5 pages, 4 tables, no figure

### Comment on "Reappraisal of the Electric Dipole Moment Enhancement Factor for Thallium"

Recent paper by Nataraj {\em et al} (Phys. Rev. Lett. {\bf 106}, 200403
(2011)) presents calculations of the EDM enhancement factor for Tl, which
disagrees with previous most accurate calculations. The authors claim that
their calculations of Tl EDM are the most accurate due to more complete
treatment of higher-order correlations. In this note we argue that this claim
is not supported by sufficient evidence. Nataraj {\em et al} also present
misleading comments about our calculations. We explain our method and reply to
the Nataraj {\em et al} comments.Comment: 2 pages, 1 figure, more discussion is adde

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